Yes, you can backup and restore the dual boot system. We need more information regarding your setup. Are the both operating systems installed on the same hard disk drive? Are they installed on different partitions or not? Do you have any other hard disk drives besides the system one?

Acronis True Image will create the backup of your two system partitions on the external hard drive. After that you will be able to restore these partitions booting from Acronis bootable rescue media (a CD or a set of diskettes).